s390/uv: UV feature check utility

Introduces a function to check the existence of an UV feature.
Refactor feature bit checks to use the new function.

Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Michael Mueller <mimu@linux.ibm.com>
Link: https://lore.kernel.org/r/20230815151415.379760-3-seiden@linux.ibm.com
Message-Id: <20230815151415.379760-3-seiden@linux.ibm.com>

diff --git a/arch/s390/include/asm/uv.h b/arch/s390/include/asm/uv.h
index d2cd42b..823adff 100644 (file)
--- a/arch/s390/include/asm/uv.h
+++ b/arch/s390/include/asm/uv.h
@@ -397,6 +397,13 @@ struct uv_info {
 
 extern struct uv_info uv_info;
 
+static inline bool uv_has_feature(u8 feature_bit)
+{
+       if (feature_bit >= sizeof(uv_info.uv_feature_indications) * 8)
+               return false;
+       return test_bit_inv(feature_bit, &uv_info.uv_feature_indications);
+}
+
 #ifdef CONFIG_PROTECTED_VIRTUALIZATION_GUEST
 extern int prot_virt_guest;
 

diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c
index b771f1b..fc07bc3 100644 (file)
--- a/arch/s390/kernel/uv.c
+++ b/arch/s390/kernel/uv.c
@@ -258,7 +258,7 @@ static bool should_export_before_import(struct uv_cb_header *uvcb, struct mm_str
         * shared page from a different protected VM will automatically also
         * transfer its ownership.
         */
-       if (test_bit_inv(BIT_UV_FEAT_MISC, &uv_info.uv_feature_indications))
+       if (uv_has_feature(BIT_UV_FEAT_MISC))
                return false;
        if (uvcb->cmd == UVC_CMD_UNPIN_PAGE_SHARED)
                return false;

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index e651160..813cc3d 100644 (file)
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2406,7 +2406,7 @@ static int kvm_s390_cpus_to_pv(struct kvm *kvm, u16 *rc, u16 *rrc)
        struct kvm_vcpu *vcpu;
 
        /* Disable the GISA if the ultravisor does not support AIV. */
-       if (!test_bit_inv(BIT_UV_FEAT_AIV, &uv_info.uv_feature_indications))
+       if (!uv_has_feature(BIT_UV_FEAT_AIV))
                kvm_s390_gisa_disable(kvm);
 
        kvm_for_each_vcpu(i, vcpu, kvm) {

diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index dbe8394..390819d 100644 (file)
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -825,7 +825,7 @@ void do_secure_storage_access(struct pt_regs *regs)
         * reliable without the misc UV feature so we need to check
         * for that as well.
         */
-       if (test_bit_inv(BIT_UV_FEAT_MISC, &uv_info.uv_feature_indications) &&
+       if (uv_has_feature(BIT_UV_FEAT_MISC) &&
            !test_bit_inv(61, &regs->int_parm_long)) {
                /*
                 * When this happens, userspace did something that it